Cause of bird flu outbreak tracked

Agriculture officials in Japan say a bird flu outbreak last week involved a highly virulent strain of the flu virus.

The Agriculture, Forestry and Fisheries Ministry said it had examined virus samples taken from chickens that died on a poultry farm in the Miyazaki Prefecture, Kyodo News reported.

In the fifth bird flu case since 2004, about 3,500 birds died at Taniguchi Furanjo Kurosaka Farm in Kiyotake.

The National Institute of Animal Health identified the virus as the H5N1 strain, a subtype of the influenza A virus. Kyodo News said the virus spreads mostly through birds and has killed more than 160 people in 10 countries since 2003, according to the World Health Organization.

In the town of Kiyotake, inspectors checked poultry farms and bird-keeping households in the area of the farm.